Then Caterpillar, a Dow component and reliable gauge of the world economy, shocked Wall Street by posting its biggest earnings miss in a decade. The maker of earth-moving equipment blamed its poor results on “lower demand” in China, one of its major markets.

Nvidia added to the doom-and-gloom by slashing its fourth-quarter sales guidance. The chip maker cited “deteriorating” economic conditions, “particularly in China.” Nvidia shares plunged 17%. And the dreary news weighed on rivals Intel, Applied Materials and Texas Instruments, all of which fell by more than 1% apiece.

Economic worries seeped into the commodity markets, where US oil prices plummeted 3.2% to $51.95 a barrel. Brent crude, the global benchmark, fell 2.2% to $60.25 a barrel. Oil stocks such as Anadarko Petroleum and Baker Hughes fell sharply.